Ruminant animals, including cattle, sheep, giraffe, deer, goats, bison and camels, and more particularly cattle and sheep, comprise an important group of animals that require periodic administration of medicines, nutrients and other biologically active agents (which are hereinafter referred to in their broadest sense as "drugs") for the treatment and alleviation of various conditions and for better health.
Ruminants have a complex three or four compartment stomach, with the rumen being the largest compartment. The rumen serves as an important location for receiving and absorbing medicines and nutrients into other compartments including the abomasum and the intestine.
There are numerous ruminal delivery devices known in the art which are capable of prolongedly releasing drugs. These devices are easily swallowed by the ruminant or otherwise introduced into the rumen and remain within the rumen for a long period of time without being regurgitated or otherwise. Typical devices are those disclosed in U.S. Pat. Nos. 4,595,583 and 4,612,186 incorporated herein by reference.
In order to insure that these devices remain in the rumen for a prolonged period of time a density element is often incorporated into the device. Typically, the density element is manufactured from a material such as iron or steel, iron shot, iron shot coated with iron oxide, magnesium alloy, copper oxide or mixtures of cobalt oxide and iron powder, and the like. Such density elements typically have sufficient density to bring the overall density of the delivery device to a level greater than the density of ruminal fluid (approximately 1 gm/ml) and preferably to an overall density of at least 2 gm/ml.
In animals such as cattle raised for slaughter the density element will often remain in the carcass after slaughter. The rumen and ruminal contents of animals still containing ruminal delivery devices, including their density elements, are typically processed by rendering plants. Rendering plants comprise a highly automated and continuous operation and though such machinery is typically equipped with magnetic retrieval systems, these systems are not always effective for removing the density elements. The rigid density elements have caused extensive and costly damage to grinder blades and equipment.
It is an object of this invention to provide a density element for a ruminal delivery device having a density sufficient to maintain the delivery device in the rumen of a living animal and also reproducibly fragment into harmless particles without damage to machinery when the density element contacts the blades in the cutting and grinding equipment of a rendering plant.
Another object of this invention is to provide a density element having a transverse rupture strength less than or equal to that of bovine or ovine bone.
A further object of this invention is to provide a corrosion resistent density element for use in a ruminal delivery device having a density sufficient to maintain the device in the rumen for a long period of time and a transverse rupture strength less than or equal to bone.
These and other objects are achieved according to the present invention.
According to an embodiment of this invention, a corrosion resistent metal powder is dry blended with a binder and compression molded into a density element which may thereafter be coated with a polymer film to increase the strength and corrosion resistance of the density element.